CVE-2016-1706 in Chrome
Summary
by MITRE
The PPAPI implementation in Google Chrome before 52.0.2743.82 does not validate the origin of IPC messages to the plugin broker process that should have come from the browser process, which allows remote attackers to bypass a sandbox protection mechanism via an unexpected message type, related to broker_process_dispatcher.cc, ppapi_plugin_process_host.cc, ppapi_thread.cc, and render_frame_message_filter.cc.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-1706 represents a critical sandbox bypass flaw within Google Chrome's PPAPI implementation that existed in versions prior to 52.0.2743.82. This issue stems from insufficient validation of IPC message origins within the browser's plugin architecture, specifically affecting the communication pathways between the browser process and plugin broker components. The flaw resides in the broker_process_dispatcher.cc, ppapi_plugin_process_host.cc, ppapi_thread.cc, and render_frame_message_filter.cc files, which together form the foundation of Chrome's PPAPI plugin security model. The vulnerability demonstrates a fundamental breakdown in the security boundary that separates the browser process from plugin execution environments, creating a pathway for malicious actors to circumvent critical sandbox protections.
The technical nature of this vulnerability can be categorized under CWE-284, which addresses improper access control mechanisms, specifically focusing on insufficient validation of inter-process communication origins. The flaw occurs because the PPAPI implementation fails to properly authenticate the source of incoming IPC messages destined for the plugin broker process. This allows remote attackers to craft and send malicious IPC messages that appear to originate from the legitimate browser process, thereby tricking the plugin broker into executing unauthorized operations. The vulnerability is particularly dangerous because it operates at a fundamental level of Chrome's security architecture, where the plugin broker serves as a critical isolation layer between the browser's trusted environment and potentially malicious plugin code. Attackers can exploit this by sending unexpected message types that bypass normal validation checks, effectively allowing them to escalate privileges and execute arbitrary code within the plugin context.
The operational impact of CVE-2016-1706 extends beyond simple privilege escalation to represent a complete breakdown of Chrome's sandboxing strategy for PPAPI plugins. This vulnerability enables attackers to bypass the intended security boundaries that protect users from malicious plugin code, potentially allowing full system compromise when combined with other exploit primitives. The flaw affects all users of affected Chrome versions and can be exploited remotely through web-based attacks, making it particularly dangerous in the context of modern browser security. The vulnerability aligns with ATT&CK technique T1059.007, which covers the use of script-based attacks, as attackers can leverage the compromised plugin broker to execute malicious code. The attack surface is significant because PPAPI plugins are commonly used for multimedia content, file system access, and other privileged operations that make this vulnerability particularly attractive to threat actors.
Mitigation strategies for CVE-2016-1706 primarily focus on immediate version updates to Chrome 52.0.2743.82 or later, which contain the necessary patches to properly validate IPC message origins. Organizations should also implement network-level controls to block access to known malicious domains and employ browser hardening techniques such as disabling unnecessary PPAPI plugins and implementing strict content security policies. The patch addresses the root cause by implementing proper origin validation checks in the broker_process_dispatcher.cc and related files, ensuring that only legitimate messages from the browser process are accepted. Additionally, security teams should monitor for indicators of compromise related to this vulnerability, including unusual IPC message patterns and unauthorized plugin activity. The fix demonstrates the importance of proper inter-process communication security and reinforces the principle that all communication channels within security-critical systems must be validated to prevent unauthorized access. Organizations should also consider implementing additional security layers such as application whitelisting and enhanced monitoring of plugin broker processes to detect potential exploitation attempts.